Crib latch



March 29, 1927.

1,622,387 F. c. MARQUARDT CRIB LATCH Filed Oct. 8, 1924 a Y W 3 T 462 y7 i IN V EN TOR.

' ATTORNEY:

Patented Mar. 29, 1927.

FREDERICK C. MAR-QUARDT, OF MILWAUKEE, WISCONSIN.

CRIB LATCH.

Application filed October 8, 1924. Serial No. 742,338.

This invention relates to improvements in latches. More particularlystated this invention relates to an improved latch mechanismparticularly adapted for use in connection with a childs crib or thelike.

It is the object of this invention to produce a novel and improved typeof latch mechanism which can be operated freely by one hand of theoperator when it is relieved of pressure but will resist every attemptto operate it on the part of a person who is unfamiliar with therequirement that the pressure must first be relieved therefrom.

In the accompanying disclosure this improved mechanism is shown inconjunction with a childs crib, a service for which it is peculiarlyadapted. Cribshaving sides which let down have heretofore ordinarilybeen provided with latches at each end of the said sides too far apartto be reached simultaneously by a child. The necessity for making itimpossible for the child to operate the latch has heretofore resulted ina device which is inconvenient for an adult since both hands of theoperator have here tofore been required to release the ordinary latch orlatches which are proof against operation by a child. The present devicecan readily be operated by the adult with one hand but, as a preliminarto its operation, the adult is required to li t slightly the side of thecrib to release the latch of pressure. It is therefore the object ofthis invention to produce a novel and improved type of latch which willcombine convenience for the operator with absolute safety againstaccidental release. The necessity for having to move the latch operatingpart in one direction after preliminarily adjusting the latch controlpart in an opposite direction makes the possibility of a childsaccidentally operating the device so remote as to be almost nonexistent.

In the drawings Figure 1 is a side elevation of a crib to which thisinvention has been applied.

Figure 2 is a section taken on line 22 of Figure 1.

Figure 3 is a detail view corresponding to the lower portion of Figure 2and illustrating a modified and preferred construction.

Figure 1 is a section taken on line 4r 4: of Figures 2 and 3.

Like parts are designated by like reference characters throughout theseveral views.

Since this invention is particularly adapted for use in connection witha crib there are illustrated at 5 and 6 the end posts of a crib having avertical adjustable side 7. The bars 8 attached to end posts 5 and 6guide the side frame 7 for its vertical movement in the usual way. Anyhorizontal rail 9 of the crib may be employed to carry the latch seat 10from which the adjustable side frame 7 may be supported.

As is freely shown in Figure 1, the side frame 7 may conveniently bemade up of top and bottom rails 12 and 13 interconnected by spindles1 1. One of these spindles, particularly designated by referencecharacter 14, may be made hollow through the provision of the centralbore 15 in which an actuating rod 16 is disposed for vertical movement.Any desired type of latch mechanism may be operated by this rod. In theparticular construction herein illustrated I have selected a very simplelatch device designated in its entirety by reference character 20 andincluding a pressed metal housing 21 in which there is, guided fortransverse reciprocation, a plunger 22 of rectangular cross sectionwhich carries a latch bolt 28 projecting from the housing through anaperture 24 therein. The plunger may have a stud 25 projectingrearwardly therefrom as a guide for a compression spring 26 whichnormally presses a bolt 23 into a position for operativeinter-engagement with the latch seat 10. For the operation of this typeof latch the rod 16 is bent at 28 to provide a cam surface 29. The lowerend of the rod is guided in aperture 30 in a housing 21 and projectsthrough a slot 32 in a plunger or guide member 22. The arrangement issuch that the downwardmovement of rod 16 will, through the interactionof cam surface 29 with plunger 22, result in a rearward movement of theplunger against a portion of spring 26 to retract the latch bolt 23 fromengagement with the latch seat 10. Upon the release of the rod 16 spring26 will expand and cause a reverse movement of the parts. The aboveconstruction may 'be'understood to exemplifyany desired type of latch. I

For the purposeof depressing rod 16 to actuate the latch I provide amanually operable button 35 which projects from the upper rail 12 ofsideframe 7. This button comprises a tube closed at its top and slotted at36 to receive the cross pin 37 in rod 16. This simple arrangementconfines the button operatively to the rod and the cross pin constitutesa convenient seat for the compression spring 38 which is housed withinthe tubular button structure. observed that the length of slot- 36 issuch as to permit button 35 to be depressed until it is received Withinthe upper rail 12 without transmitting any positive motion to the shaft16. The depression of the button simply compresses spring 38 and. ifshaft or rod 16 is free to move downwardly the con'ipression of spring33 will be relieved by such downward movement. If, however,

: the downward movement of shaft or rod 16 is opposed by a resistancegreater than the pressure required to compress spring 38, it willobviously be impossible for the operator to cause the rod 16 to move.

Such a resistance is furnished in the present device by the frictionalengagement of latch bolt 23 with seat 10 and by the friction existingbetween the parts required for the retraction of the said bolt togetherwith the pressure of spring 26 resisting such retraction. It has beendemonstrated by actual tests that if the operator slightly lifts theside frame 7 of the crib and subsequently depresses button 35 thecompression of spring 38 may be entirely adequate to retract the boltagainst the compression of the relatively lighter spring 26. If,however, the weight of the crib side frame 7 is supported from the cribframe proper through the latch bolt 23 and stop 10, the resultingfriction will so increase the resistance to movement of rod 16 as toprevent retraction of the bolt regardless of any attempts on the part ofthe operator to press downwardly on button 35. Obviously the tendency ofthe operator is to press upon the latch confined part in the directionin which it is expected that this part will move if the latch isreleased. As a consequence the uninformed person, in attempt ing tooperate this latch isapt to add some degree of weight to the weight ofthe crib side 7 and thereby render even greater the resistance ofthelatch to the attempted op eration. I

In the construction above disclosed, it is necessary to arrive at apredetermined balance between the forces required to compress thesprings 38 and 26, and as has just been explained it is necessary thatspring 38 be sufiiciently strong to overcome spring 26 unless the spring26 is aided by the friction between the parts, and at the same time thespring 26 must be sufficiently strong so that when assisted by saidfriction it will produce adequate resistance to overcome the pressure ofspring 38. This balance is readily obtainable and the device whenconstructed as indicated is very satisfactorily operable, but forcommercial manufacture It will be it is preferableto employ aconstruction in which no. such balance is required. For this purpose itis only necessary to modify the latch stop 10 in the manner indicated at10 in Figure 3 to provide an upwardly extending flange 39 and to formthe latch bolt 23' with a shoulder at 40 adapted for positiveinter-engagement with the flange This arrangement, in which the positiveinterlockingengagement exists between the bolt 23' and stop 10 in amanner adapted normally to provide a retraction of the latch bolt, makesit unnecessary to figure on friction. It is only necessary to make surethat the spring38 is sufliciently strong to overcome spring 26 and toprovide retraction of the bolt when the bolt is free to move. In orderto avoid any necessity for close cal culation of this minimum strengthof spring 38, I have illustrated in the modified construction a devicein which the springs may be made as powerful asis desired. It will beobvious that when the parts are in interlocking engagement no amount ofpressure on button 35 regardless of the strength of spring 38 willretract the bolt. Whereas in the Figure 2 construction, it is sufficientmerely to relieve. the bolt 23 of the weight of the side frame 7 withoutactually lifting such frame, in the Figure 3 construction it isnecessary actually to lift the side frame until the shoulder 10 clearsflange 39.

It will be seen from the foregoing that the latch mechanism hereindisclosed is such that it requires for its operation a preliminaryadjustment which is contrary to the normal expectation of a personattempting to operate the latch. At the same time this adjustment is sosimple and can so readily be performedby a person acquainted with itthat it complies with the objects expressed for this invention. Thenormal method of operation will involve the placing of the operatorsfingers beneath the rail bar 12 and the-operators thumb upon button 35,a simultaneous operationof the fingers and downward movement of thethumb, as if in naturally compressing the hand, will result in therelease of the latch for downward movement of the crib frame 7 The framemay readily be restored to its lifted position since the latch bolt isprovided in the usual manner with a bevel upper surface which, intheupward movement of the side frame 7, interacts with the plate 10tothrow the bolt aside.

I claim:

1. In a device of the class described, a seat for a latch-bolt, a latchbolt arranged toengage said seat when in operative position and tosupport a load thereon, an operating part for said latch-bolt having aresilient connection therewith, the strength of said connection being,so related to the re sistance of said bolt that it is adapted to retractsaid bolt from said seat only when the latter is relieved of load.

2. In a device of the character described, the combinationwithrelatively fixed and movable members and a latch bolt and seatrespectively connected with said members, said movable member having atendency to move with respect to said fixed member and said bolt beingadapted normally to interact with said seat to restrain such movement,of manually operable means impositively connected with said latch boltfor the retraction thereof from said seat, the impositive connectionbetween said means and said bolt being normally inadquate for theretraction of said bolt while said bolt is operative to restrain saidmovable member as aforesaid, and being adequate for the retraction ofsaid bolt when said bolt is not operative to restrain said movablemember from movement.

3. In a device of the character described, the combination with a latchseat element, of a latch bolt element retract-able with reference tosaid seat and formed for interlatching engagement with said seat elementin a manner adapted to oppose positively such retraction, and resilientmeans operable upon said bolt element in a direction tending to retractsaid bolt element from said seat element upon disengagement of saidinterlatching elements.

' 4. In a device of the character described, the combination with alatch seat and a member adjustable with reference thereto, of a boltmovable between advanced and retracted positions and adapted in itsadvanced position to contact said seat, whereby to support the load ofsaid member and to restrain said member from adjustment with referencethereto, an actuator for said bolt adapted to move said bolt'toward itsretracted position, a manually engageable part, and a spring interposedbetween said part and said actuator, said spring having a strengthsutlicient to transmit movement from said part to said actuator in adirection to retract said bolt when said bolt is relieved of the load ofsaid member.

5. In a device of the character described, the combination with a latchseat, of a bolt retractable therefrom, said seat and said bolt beingprovided with interlocking shoulders adapted normally to prevent suchretraction, a member supported by said bolt from said seat and adaptedfor movement in a direction to aiiord clearance between the saidshoulders of said bolt and said seat, whereby said bolt is retractable,and means for retracting the bolt, said means including a manuallyoperable part and impositive motion transmitting connections betweensaid part and said bolt and operatively adapted for the retraction ofsaid bolt.

6. In a device of the class described, a seat for a latch-bolt, a latchbolt arranged to engage said seat when in operative position and tosupport a load thereon, an operating part for said latch-bolt having ayield ing spring connection therewith, the strength of said spring beingso related to the resistance of said bolt that it is adapted to retractsaid bolt from said seat only when the latter is relieved of load.

FREDERICK C. MARQUARDT.

